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Maha MH C808M Charger

Maha has stepped up to the high capacity charging challenge by offering a new charger in their line up. The C808M is capable of charging AAA, AA, C, and D cells. It defaults to charging at 2 amps, so it does not take an extended period of time to charge up high capacity cells. My 9000 mAh D cells use to take around 36 hours to charge on my Vanson Speedy Box. Using the C808M, it only takes around 6 hours. That is a vast improvement.

This charger has 8 independent charging bays and charges AAA, AA, C, and D NiMh or NiCd cells. You can mix and match to your hearts content, but once the charge rate or conditioning cycles is set, it is set for all 8 bays. You can not be conditioning cells in bays 1 and 2, then set it up to charge cells in the other bays. The choices are:
1. default charging (0.7 amps for AAA cells and 2.0 amps for AA, C, and D cells),
2. soft charging at half the default charging rate, or
3. conditioning.
The conditioning cycle first charges the cells (at either the default rate or the soft rate), then discharges them at 0.25 amps EDIT It seems I was a bit off on this, it is more like 350 mA but see post #54 for the real numbers END EDIT, then charges them back up again. At the end of the charging cycles, a trickle charge of 0.007 amps keeps the cells ready to go. This low trickle charge rate may make this the only charger that you can leave your cells in for an extended period of time without harm. I do not recommend leaving batteries on trickle charge, but if you want to do that, this is the charger for you.

The C808M comes with a 3 year warranty from Maha.

The C808M does not use springs in its contact set up. It has individual contacts for each size of battery. This makes for a very robust set up, and allows some spacing between cells to keep them cool. The trade off is that the unit has some size to it. The dimensions of the charger unit are EDIT Oops 7.5” x 3.5” x 1.75” is for the C801D the C808M is 12.63" x 5.25" x 3". END EDIT In addition it is powered by an AC switching adapter that is 5.125” x 2.25” x 1.185”. The power supply input is rated at 100-240 volts 50-60 hertz, so it will work worldwide. It uses a maximum of 1200 mA. Mine came with a North American 2 prong blade plug, but you can get power cords to match the outlet style where you are. The power supply uses a DIN plug to connect to the charger. There is no 12 volt DC power provision.

The back lit LCD display shows a graphic of what is going on in each slot and also displays the English words Condition, Charge, and when the charge is completed, the word Done is displayed for each slot. When an error occurs, the word Done will be flashing in the slot where the error occurred. The graphic is the outline of a battery with three bars in it. During discharging, the outline disappears and the bars change from three, to two, to one, then none at all. When charging starts, the outline comes back on. The charging progress is displayed by the three bars until “Done” indicates the beginning of the trickle charge.

A very soft “click” can be heard as the unit charges. This is a result of the pulse charging used while charging, and also while on trickle charge.

You have to pay attention when inserting the cells for charging. The negative end goes in first and then you press down to snap the positive end in place. AAA cells are placed in the bottom and to the right. I had some initial difficulty getting them in the right place, but when I looked at what I was doing, there were no more difficulties. I have noticed that I often don’t get the AA cells completely snapped into place. The display is very good at letting you know that the cell is not in place, because there will be no graphic display.

The right side of the unit gets warm during discharge, and you are instructed to insert cells starting from the left side. I asked Maha about this, and they said it was simply to keep the cells cooler. You are also instructed to put the larger cells on the left side and work your way right with smaller cells. Once again Maha says that they are trying to keep the heat down.

The operators manual also states that you should not leave an empty slot when putting your cells in for charging. Maha does not know why that statement is in there… Anticipating some problems, I did a number of tests starting from right to left, filling the middle slots, and skipping every other slot. The C808M took it all in stride and performed flawlessly. It truly is an independent 8 channel charger – with no restrictions.

I did have some problems charging NiCd AA cells. It seems that they end up at a higher voltage than the C808M thinks they should and I ended up with an error signal. I also tried to charge some Alkaline AA cells and got the same error signal. I talked with Maha about this. They indicated that the charging algorithm was designed for NiMh chemistry, and it should work well with NiCd chemistry as well, but I was finding a bit of a difference. The cells did end up fully charged, they just ended on an error signal and the trickle charge was terminated.

So, if you are charging NiCd cells, you may run into this same thing. Please note that this did not occur with every cycle. Sometimes everything came out fine, but other times I would get the error signal.

The cells come off the charger warm. The highest temperature I observed was 96 F. Maha claims the high temperature cut off is set at 120 F. The charging is consistent from bay to bay.

I am used to cells coming off the charger at around 1.45 volts. My cells came off the C808M at 1.43 volts. This charger is right there at the top of the pack as far as complete charging goes. The AccuManager 20 just barely beat it out, and it does slightly better than the BC-900. It also just barely beats the Vanson Speedy Box after the charge has completed and the cells have trickle charged for an additional 24 hours.

I am very pleased with the C808M. It will take very good care of your cells during charging and won’t cook them during trickle charging. It also does a very good job of packing a lot of capacity into your cells.

The only error I noticed was while charging NiCd cells, and when I tried to “trick” it into charging Alkaline cells. I believe the NiCd error was because the voltage went higher than expected.

I can give this charger a big “thumbs up” and highly recommend it.

Tom

Edit: I forgot to mention that this charger does not have a on/off switch. The LCD display comes to life when you put a cell in to charge, and goes off when you remove all the cells.

I received an eMail from William at Maha Energy. He explained that the flashing Done that I am seeing while charging NiCd cells is not an error. It is just indicating that the charge was terminated on high voltage rather than delta voltage. He is considering revising the operators manual to include this information.

By the way, William is the one that sent me the charger to check out. Thanks William!!! If you have any questions, William is the one that programed the charging algorithm used by this charger. He has been most helpful in helping me understand how this charger works. If you have questions, let me know, or get in touch with William directly at www.mahaenergy.com .

Another Edit:

Some people have noticed that the 808 will flash "Done" when charging NiCd cells. This interrupts the conditioning cycle and makes that cycle useless for NiCd cells. This is unfortunate because NiCd cells need to be conditioned more often than NiMh cells do.

This does not happen with every NiCd cell, but it appears that the 808 will terminate the charge when the voltage reaches 1.6 volts. This keeps people from trying to charge alkaline cells. Some NiCd cells bump against this 1.6 volt cut off, resulting in the flashing "Done" and ending the cycle.

William was kind enough to reveal a work around for this. You put 1 NiMh cell in slot 1 and select conditioning. When the cell enters the discharge phase, you load up the other slots with your NiCd cells. Once the unit has entered the discharge phase, it does not try to charge the additional cells before discharging them. The results will be a conditioned NiCd cell. You may end up with a flashing "Done" at the end of the charge cycle, but the cell will have gone through the discharge cycle and should be conditioned.

I must add that I have been using this charger for several months now and still am very pleased with it.

Last edited by SilverFox; 07-21-2006 at 08:41 AM.

Behind every Great man there's always a woman rolling her eyes...

Most batteries don't die - they are tortured to near death, then murdered...

Re: Maha MH C808M Charger

Finally!
A charger that can handle all 8 of my nFlex WX1S LuxeonV 8AA Mag mod! Although I shy away from charging AA cells at 2 amps, the soft charge 1 amp option should work fine on my Sanyo Industrial 1700mAH NiMH AA cells. The only option I wish for is for it to display the capacity after conditioning the cells. Always nice to know if one of the cells is getting weak taking the packs performance down.
My BC-900 won't condition on one of the bays and it is a PIA to get the damned thing to conditon (what crackhead designed the human interface!?) Luckily, we have our new Cadex $3,700 NiCad, NiMH, Lead Acid, AGM, Lithium-Ion, Lithium-Polymer and primary lithium cell (3 minute test tells the condition of primary lithium cells for defibrillators... top that!)
Maybe Maha will come out with one that displays the capacity of the cells one day....

Re: Maha MH C808M Charger

Update:

William of MahaEnergy told me that the flashing Done that I am seeing at the end of the charge while charging NiCd cells is not an error message. It simply means that the charge was terminated on high voltage, rather than on delta voltage.

I also added some information about the lack of an on/off switch in the first post.

Tom

Behind every Great man there's always a woman rolling her eyes...

Most batteries don't die - they are tortured to near death, then murdered...

Re: Maha MH C808M Charger

Tom, thank you very, very much for the thousands of hours (probably more) that you have spent on battery, battery technology and battery chargers research and the resultant knowledge passed along to all of us. Whenever I see a new thread that you've started, I get a jolt of excitement and click on it immediately! I love to read your posts! thank you, Thank You, THANK YOU!!

Mine arrived last week and its worked exactly as you describe. I, too didn't realize until the 2rd batch of batteries that I had not snapped the AA's fully into place. They'll charge without being fully in-place. My only very slightly negative observation is that the vertical viewing angle of the display is a little lower than I'd like. If you view the display at 45 degrees or above, the icons "gray out" a bit. So if you stand over it, the icons will be faint. If you view it from in-front and low, they are "bright".

Re: Maha MH C808M Charger

Thanks Tom,
I will probably pick up the C808M after what I have been reading about the LaCrosse BC-900 charger/conditioner. Don't like the idea of flaming batteries, melted buttons and it's ability to start things on fire. I can use the BC-900 for measured conditioning only at higher 700mA charge rates but need an 8-bay for general charging.
Accucharger 4 bay at home and C808M 8-bay at work or travel (were I keep my 8AA Mag) Rather large charger but worth it when charging 8 batteries or dealing with different voltages in different countries.

Re: Maha MH C808M Charger

Many thanks for the review Tom, and for all the information you provide here on CPF!

I recently decided to go with rechargeables and started researching the best charger and cells for the job. I can't tell you how valuable the information you have provided is to me, and with a depth of knowledge and experience I could never hope to match!

Re: Maha MH C808M Charger

The MH C801D looks good to me. $30 cheaper than the 808. Looks like the only difference is it only charges AA/AAA. Don't know how long their Holiday Special will go on though.

I agree with bc5000 :
I've had my C801D for a month now. Since the 808 also charges C & D batt's , I assumed it would also have to be a little larger in size to accomidate them. I'm glad they make the 801D at a -$30 reduction for us who only use AA/AAA.

One thing that appealed to me was the very low current ' trickle charge ' which wont 'cook' the batt's. Thus allowing me to leave 4 aa & 4 aaa's in there ready for use. Also nice is the ability to select the 'soft charge mode' which should increase batt life and charge them closer to maximum capacity b-4 shut-off.

A CAUTIONARY REMINDER : As stated in the 1st paragraph of the instructions. DO NOT use the (default) one-hour rapid charge mode on AA batteries rated UNDER 2000mAh and AAA batteries UNDER 700mAh. To charge them,use the 'soft-charging mode', which means press the soft-charge 'button' after you insert the 1st battery into the far left slot. ( If you put a single battery in the charger that's rated less than 2000mAh it will be getting "Fast charged" @ a rate of 2.0A which is too much current.........unless you press the "soft-charge" button to change the charge " mode " just after putting the batt. in ) .......o.k. ?

I mention this , as many of us are still using 1200,1400 and 1800mAh NI-MH batt's and even some lower mAh NICAD's. It is SO easy to forget and pop-in a less than 2000mAh batt and walk away. The charger will be charging a lower mAh batt at 2.0A (aa) or 0.7A (aaa) which is higher than the overall rating of the battery itself. This I believe might be a fire and melt-down hazard which we are all more cautious of since the latest LaCrosse 900 issues. Over-all I am pleased with my 801D and recomend it with only these 3 minor complaints :

1: As pointed out by BVH to SilverFox on the C808M model (which it appears is similar to the C801D ) the verticle viewing angle of the LCD display makes it hard to read without getting down to it's level .

2: The LCD display has tiny lettering and is hard for me to read - even with reading glasses .

3: It is very hard and annoying to get the batt's back out of the slots without prying them out from the + end with some type of sharp tool - which over time chews-up and damages the covering label of the batt. at the + end and may cause it to tear and start coming off. I dont like it when my batteries loose their descriptive label.Do you? However even I don't have a re-design suggestion to make removal easier.

Other than that..... The C801D seems to be a great charger just like the C808M of SilverFox's report.

Many thanks to SilverFox for his analysis work. I'm sure it's appreciated by all of us.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Edited 1/17/2006 by TooManyGizmos to add an update.

Batteries are too hard to remove from the 801 model , so I'm returning mine to exchange for the 808 model which might be more "user-friendly" . ? ?

************************************

We cant have.........TooManyGizmos

Last edited by TooManyGizmos; 01-17-2006 at 04:57 PM.
Reason: added 1 more detail

Re: Maha MH C808M Charger

How risky is it to charge a cell over a 1C rate with this charger? The Energizer 15min charger charges well over 1 C. It seems highly probable that people (such as myself)will forget to soft charge batteries of lower capacities. Maybe that's why they call it a professional charger......dangerous in the hands of amateurs.

Re: Maha MH C808M Charger

Originally Posted by TooManyGizmos

3: It is very hard and annoying to get the batt's back out of the slots without prying them out from the + end with some type of sharp tool - which over time chews-up and damages the covering label of the batt. at the + end and may cause it to tear and start coming off. I dont like it when my batteries loose their descriptive label.Do you? However even I don't have a re-design suggestion to make removal easier.

How about a length of ribbon/tape laid across the bays (under the cells) and fixed at one end. You just need to lift the other end to pop the cells out.
I've seen this in the battery compartments of a few devices and it seems to do the trick.

Re: Maha MH C808M Charger

Originally Posted by D MacAlpine

How about a length of ribbon/tape laid across the bays (under the cells) and fixed at one end. You just need to lift the other end to pop the cells out.
I've seen this in the battery compartments of a few devices and it seems to do the trick.

Don

Concerning the MaHa MH C801D (AA&AAA only charger)....
Thank you Don , that works very well to remove all the cells at one time , but when charging 8 cells of varying discharge status , they all get done charging at varied times. All the cells are so close together that they almost touch each other . When you want to remove a cell thats done charging somewhere in the middle of the 8 , there in lies the difficulty.

Keep in mind , while I try to explain this , that when the battery is fully inserted, the negative 'springy' terminal pushes the batt. quite strongly towards the positive terminal .

The negative end of the batt. is totally flat and very slick , which does not allow prying out from that end . The pry-tool has nothing to grip so it just slips out.

The stationary positive charging terminals are 'recessed' a little under the plastic housing of the charger at each slot. So the batt. can't come straight up & out cause it gets caught on the recess lip of the case. Therefore you must insert pry-tool above the positive terminal of the batt. and push the batt. toward the negative 'springy' charger terminal as you pry the batt. up and out......whew .

That strong prying action is what damages the wrapper label on the battery . It's just plain difficult to get one battery out of the charger so you can insert another to charge . I can't find any other way to get em out !

Re: Maha MH C808M Charger

TMG, the 808 is quite different. Because its made to charge the larger C and D cells also, (near the top of the charger) there's tons of room/spacing between AA's & AAA's at the bottom of the charger. If, however, you were charging C's or D's, you might have the same issue. Don't have any so have not tried. Must admit, the AA's look lost way down there in the bottom of the charger. Look at the dimensions of both. The 808 is quite a bit bigger. The more mass/surface area/space between cells probably results in better cooling.

Re: Maha MH C808M Charger

Originally Posted by BVH

TMG, the 808 is quite different. Because its made to charge the larger C and D cells also, (near the top of the charger) there's tons of room/spacing between AA's & AAA's at the bottom of the charger. If, however, you were charging C's or D's, you might have the same issue. Don't have any so have not tried. Must admit, the AA's look lost way down there in the bottom of the charger. Look at the dimensions of both. The 808 is quite a bit bigger. The more mass/surface area/space between cells probably results in better cooling.

Re: Maha MH C808M Charger

Hello John,

I have not tested the Ansmann Energy 16 charger, but the specifications indicate that it is capable of charging 9V batteries, where the Maha C808M is not. Charging C or D sized cells, the Ansmann will only do 6 cells at a time, where the Maha will do 8. Another difference is the charging rates. The Ansmann charger will take roughly 20 hours to charge a 10000 mAh D cell, where the Maha will only take about 7 hours.

I don't know what current the Ansmann uses for trickle charging, but the Maha's very low trickle charge current is easy on your cells.

Tom

Behind every Great man there's always a woman rolling her eyes...

Most batteries don't die - they are tortured to near death, then murdered...

Re: Maha MH C808M Charger

Hello TooManyGizmos,

During my testing, I did several charge cycles with 1000 mAh, 1200 mAh and 1500 mAh AA cells, charging at the fast rate (2.0 Amps). I also tested some 600 mAh AAA cells at the fast rate. I did not encounter any battery heating problems at all and all these lower capacity cells charged without problems.

I still think it is prudent to remember the Maha warning, but they may be being a bit conservative...

Edit to add... I have experienced no problems removing any sized cells from the C808M charging bay. There can be some difficulties in getting AAA cells properly inserted, but after you do it a few times, it is not that difficult at all. On the C808M, the key seems to be to insert the - end first, then snap the + end in. Upon removing the cells, you remove the + end first and the cell pops out. There is ample room between AA and AA cells to grab the whole cell and pull it out. C and D cells sit above the top plane of the charger, so they are also easy to install and remove.

Tom

Last edited by SilverFox; 01-17-2006 at 11:46 AM.

Behind every Great man there's always a woman rolling her eyes...

Most batteries don't die - they are tortured to near death, then murdered...

Re: Maha MH C808M Charger

Hello Ben,

Heat destroys NiMh cells. Charging above 1C can generate heat, however it is possible to do it with an advanced charging algorithm. The bottom line is that if the cells heat up, slow down the charge rate... unless you are involved in RC racing.

Tom

Behind every Great man there's always a woman rolling her eyes...

Most batteries don't die - they are tortured to near death, then murdered...

Re: Maha MH C808M Charger

Originally Posted by SilverFox

Hello TooManyGizmos,

During my testing, I did several charge cycles with 1000 mAh, 1200 mAh and 1500 mAh AA cells, charging at the fast rate (2.0 Amps). I also tested some 600 mAh AAA cells at the fast rate. I did not encounter any battery heating problems at all and all these lower capacity cells charged without problems.

I still think it is prudent to remember the Maha warning, but they may be being a bit conservative...

Edit to add... I have experienced no problems removing any sized cells from the C808M charging bay. There can be some difficulties in getting AAA cells properly inserted, but after you do it a few times, it is not that difficult at all. On the C808M, the key seems to be to insert the - end first, then snap the + end in. Upon removing the cells, you remove the + end first and the cell pops out. There is ample room between AA and AA cells to grab the whole cell and pull it out. C and D cells sit above the top plane of the charger, so they are also easy to install and remove.

Tom

Thank you SilverFox , I am returning my 801 model & getting the 808m model that you reviewed . I will make a seperate new post about the MaHa MH C801D issues .

Re: Maha MH C808M Charger

Originally Posted by SilverFox

Hello John,

I have not tested the Ansmann Energy 16 charger, but the specifications indicate that it is capable of charging 9V batteries, where the Maha C808M is not. Charging C or D sized cells, the Ansmann will only do 6 cells at a time, where the Maha will do 8. Another difference is the charging rates. The Ansmann charger will take roughly 20 hours to charge a 10000 mAh D cell, where the Maha will only take about 7 hours.

I don't know what current the Ansmann uses for trickle charging, but the Maha's very low trickle charge current is easy on your cells.

Tom

Tom,

My next charger will be the MH-C808M, especially for my CTA 12000mAh D cells!